Compact deployment of YouCompleteMe

Intelligent code completion in C++ is best done with
YouCompleteMe
in my opinion. It’s fast, precise, clever and easy to install. However,
default installation occupies much space in file system. For example,
after just python2 install.py --clang-completer:

Thus, half of a gigabyte for C#, Go, Rust completion engines, boost and clang
copies. It’s a good thing to have self-contained deployment, independent from
specific distribution environment. But I’d like to have more compact
installation.

First step was to use system libclang and boost. This isn’t recommended by the
plugin author, by the way. After adding tuning the build to
python2 install.py --clang-completer --system-libclang --system-boost:

Still a quarter of gigabyte. Then drastic cut: implement custom deployment.
The script update-ycm.sh
does few things:

Clones the latest version of YouCompleteMe from github

Builds it with clang completer enabled linking with system libraries

Removes fat bits and pieces

Deploys the stripped plugin into ~/.vim

Updates global ycm_extra_conf.py to match include paths of system clang.